Phase imaging of irradiated foils at the OMEGA EP facility using phase-stepping X-ray Talbot-Lau deflectometry

Diagnosing the evolution of laser-generated High Energy Density (HED) systems is fundamental to develop a correct understanding of the behavior of matter under extreme conditions. Talbot-Lau interferometry constitutes a promising tool, since it permits simultaneous single-shot X-ray radiography and phase-contrast imaging of dense plasmas. We
present the results of an experiment at OMEGA EP that aims to probe the ablation front of a laser-irradiated foil using a Talbot-Lau X-ray Interferometer. A CH foil was irradiated by a laser of 133 J, 1 ns and probed with 8 keV laserproduced backlighter radiation from Cu foils driven by a short-pulse laser (153 J, 11 ps). The ablation front interferograms
were processed in combination with a set of reference images obtained ex-situ using phase-stepping. We managed to obtain attenuation and phase-shift images of a laser-irradiated foil for electron densities above 1022 cm−3. These results showcase the capabilities of Talbot-Lau x-ray diagnostic methods to diagnose HED laser-generated plasmas through
high-resolution imaging.